1. Field of the Invention
The present invention relates generally to a method and system for enabling device functions, and more specifically to a method and system for enabling communications functions in a local wireless device based on a distance between the local wireless device and a remote wireless device.
2. Discussion of the Background
The recent proliferation of hand held computers has made data exchange between wireless devices such as mobile phones, laptops, and hand held devices more common. In this proliferation, various wireless communications technologies including infrared technology and radio frequency (RF) technology have emerged to provide the wireless connectivity between devices. With regard to infrared technology, the Infrared Data Association (IrDA) has specified several infrared communications standards to provide the wireless connectivity necessary for data exchange between devices. IrDA is a point to point narrow angle ad hoc data transmission standard designed to operate at distances of 1 meter or so. In the area of RF connectivity, Blue tooth technology has been recently proposed as an RF specification for providing a wireless communications link between devices. Blue tooth employs an omnidirectional signal transmitted at 2.4 GHz and provides a normal link range of 10 cm to 10 m in non-line of sight transmission through solid objects such as walls and other structures.
A common wireless data exchange scenario is one in which the exchange will take place in a room containing a number of other wireless devices making similar data exchanges. An example is an electronic business card exchange where two people meet to exchange business cards, face to face, in a large conference room where many other people carrying wireless devices are also present in the room and making similar exchanges. As another example, a person may want to download photographs from a digital camera to a wireless kiosk in a retail store where other digital cameras and wireless devices are exchanging data. In each of these situations, the wireless devices of the intended transaction must provide some way of filtering the data of the intended transaction from other data in the area. That is, the devices of the business card exchange must provide some way of sending and receiving only the intended business card and blocking other business cards that are being exchanged in the conference room, and the kiosk must be able to distinguish the intended photographs from other data.
The IrDA infrared technology provides such a filtering function by requiring the users of the device to “point and shoot” the electronic data from the sending device to the intended receiving device. The limited range and narrow beam width of IrDA provides a way of filtering out unintended signals and ensuring communications only between intended devices. In the examples discussed above, the sender of an electronic business card would simply position his device within one meter of the receiving device, and then pointed directly at the receiving device and press a send button that transmits the electronic business card to the receiving device on an infrared beam. The camera owner would similarly point and shoot the photographs to the kiosk. As recognized by the present inventors, the infrared system is problematic, however, in that the infrared devices must be placed in a fixed location of close proximity and precise orientation while synchronization and data exchange takes place between the two devices. This positioning makes transactions with fixed structure devices such as the kiosk inconvenient. Moreover, IrDa technology requires that the data exchanging devices be within line of sight of each other making it impossible for one device to transmit an electronic business card to another device located in the intended recipients pocket or briefcase. A deficiency observed by the present inventors is that the line-of-sight nature of infrared communication links is that it requires the user's vision is a necessary step to properly orient the IR transmission beam. Thus, avoiding the possibility of being used effectively by visually impaired people, by remote “un-manned” equipment or in other scenarios where manual beam pointing is inconvenient or impossible.
On the other hand, the characteristics of the omnidirectional RF signal devices such as Blue tooth devices allows communication over relatively far distances and provides signals that penetrate solid objects. Therefore, RF devices provide maximum mobility for the user and the capability to communicate with obstructed devices. In order to distinguish intended data from unintended data, the RF device must perform a discovery operation that will find many sending devices other than the intended device. While these additional capabilities carry great benefits for the user, one problem is that the user is then forced to choose from a list of discovered devices which requires special information about the sending device such as a device bit address or name that is associated with the user of the device. Moreover, because modern RF devices have multipoint capabilities and therefore utilize security mechanisms to prevent unauthorized access, the users of the devices of the intended exchange may also have to execute security measures. These procedures are time consuming and impractical for many data exchanges such as the typical electronic business card and photo exchange discussed above.